ENANTIOSELECTIVE INTRAMOLECULAR AZA-SPIROANNULATION ONTO BENZOFURANS USING CHIRAL RHODIUM CATALYSIS
ENANTIOSELECTIVE INTRAMOLECULAR AZA-SPIROANNULATION ONTO BENZOFURANS USING CHIRAL RHODIUM CATALYSIS
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DOI：
10.3987/com-14-12941
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发表时间：
2014-03-01
期刊：
影响因子：
0.6
通讯作者：
Iwabuchi, Yoshiharu
中科院分区：
文献类型：
--
作者：
Shibuta, Takuro;Sato, Shigeki;Iwabuchi, Yoshiharu
报道了在手性铑催化下对苯并呋喃进行高效、对映选择性的分子内氮杂螺环反应的研究进展。在优化的反应条件[Rh-2(S-三氯丙烷)(4)(3mol%)，邻苯二甲酸二异辛酯(1.6当量)，甲醇(10当量)在PhCF3中，0℃]下，3-(氨基甲酰甲基)苯并呋喃(3)的氧化氮杂螺环合成了(2R，3S)-2-methoxy-2H-spiro-[benzofuran-3，4‘-oxazolidin]-2’-one(15a)，产率为69%，ee为86%，其绝对结构由X射线结晶学和振动圆二色谱确定。该反应适用于C3(高达92%ee)含氮四取代碳立体中心的各种2，3-二氢苯并呋喃衍生物的不对称构筑。
The development of efficient and enantioselective intramolecular aza-spiroannulation onto benzofurans using chiral rhodium catalysis is described. The optimized reaction conditions [Rh-2(S-TCPTAD)(4) (3 mol %), PhIO (1.6 equiv), MeOH (10 equiv) in PhCF3, 0 degrees C] brought about oxidative aza-spiroannulation of 3-(carbamoylmethyl)benzofuran (3) resulting in (2R,3S)-2-methoxy-2H-spiro-[benzofuran-3,4'-oxazolidin]-2'-one (15a) in 69% yield with 86% ee, the absolute structure of which was determined by a combination of X-ray crystallography and vibrational circular dichroism (VCD) spectroscopy. The reaction is applicable to the asymmetric construction of various 2,3-dihydrobenzofuran derivatives bearing a nitrogen-containing tetrasubstituted carbon stereocenter at C3 (up to 92% ee).